DBD::DB2: setting the application name

DB2 allows client applications to set the application name using the 
SQL_ATTR_INFO_PROGRAMNAME attribute.  If you have a number of perl 
applications connecting to the same database, this allows you to 
distinguish between them by setting the application name to the script / 
library name instead of the default "perl".  The application name set is 
visible when an administrator performs "list applications".

I have long wanted to do this from DBD::DB2.  I asked IBM to add this to 
the driver and received an internal defect number for this (166029); 
however, the latest DBD::DB2 release (1.3) does not include this feature.

The attached patch shows how this feature can be added.  I hope IBM gets 
around to including this in the next DBD::DB2 release; in the meantime, 
other users of DBD::DB2 may benefit from this change.

This feature is used as follows:

   my $dbh = DBI->connect("dbi:DB2:$dsn", $userid, $password,
                          { 'db2_application_name' => $name });

Cheers,
   Hildo Biersma

*** dbdimp.c.orig	Tue Dec 30 10:03:29 2008
--- dbdimp.c	Tue Dec 30 10:02:58 2008
***************
*** 417,422 ****
--- 417,440 ----
        if( SQL_SUCCESS != ret )
          goto exit;
      }
+ 
+     pval = hv_fetch( attrh, "db2_application_name", 20, 0 );
+     if(pval && SvOK(*pval)) {
+         STRLEN vl;
+ 	SQLPOINTER app_name;
+ 	SQLINTEGER app_name_len;
+ 
+         app_name = (SQLPOINTER)SvPV(*pval, vl);
+         app_name_len = (SQLINTEGER)vl;
+ 
+ 	ret = SQLSetConnectAttr(imp_dbh->hdbc,
+ 				SQL_ATTR_INFO_PROGRAMNAME,
+ 				app_name, 
+ 				app_name_len);
+ 	ret = check_error( dbh, ret, "Set application name failed" );
+ 	if( SQL_SUCCESS != ret )
+ 	    goto exit;
+     }
    }
  
    /* If the string contains a =, use SQLDriverConnect */